Ex Parte Ho et alDownload PDFPatent Trial and Appeal BoardMay 18, 201814552086 (P.T.A.B. May. 18, 2018) Copy Citation UNITED STA TES p A TENT AND TRADEMARK OFFICE APPLICATION NO. FILING DATE 14/552,086 11/24/2014 65913 7590 05/22/2018 Intellectual Property and Licensing NXPB.V. 411 East Plumeria Drive, MS41 SAN JOSE, CA 95134 FIRST NAMED INVENTOR Chung Hsiung Ho UNITED STATES DEPARTMENT OF COMMERCE United States Patent and Trademark Office Address: COMMISSIONER FOR PATENTS P.O. Box 1450 Alexandria, Virginia 22313-1450 www .uspto.gov ATTORNEY DOCKET NO. CONFIRMATION NO. 81639293US01 7615 EXAMINER CAMPBELL, SHAUN M ART UNIT PAPER NUMBER 2829 NOTIFICATION DATE DELIVERY MODE 05/22/2018 ELECTRONIC Please find below and/or attached an Office communication concerning this application or proceeding. The time period for reply, if any, is set in the attached communication. Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the following e-mail address(es): ip.department.us@nxp.com PTOL-90A (Rev. 04/07) UNITED STATES PATENT AND TRADEMARK OFFICE BEFORE THE PATENT TRIAL AND APPEAL BOARD Ex parte CHUNG HSIUNG HO, BENSONIL CHAN, and CHIEN KUO Appeal2017-007355 Application 14/552,086 Technology Center 2800 Before DONNA M. PRAISS, CHRISTOPHER L. OGDEN, and DEBRA L. DENNETT, Administrative Patent Judges. PRAISS, Administrative Patent Judge. DECISION ON APPEAL 1 STATEMENT OF THE CASE This is an appeal under 35 U.S.C. § 134 from the final rejection of claims 1---6. Final Act. 3-7; App. Br. 3. We have jurisdiction under 35 U.S.C. § 6(b ). We AFFIRM. The subject matter of this appeal relates to a process for sawing a low dielectric constant wafer substrate having active devices so as to minimize 1 In explaining our decision, we make reference to the Specification filed November 24, 2014 ("Spec."), the Final Office Action mailed March 16, 2016 ("Final Act."), the Appeal Brief filed October 24, 2016, as corrected November 16, 2016 ("App. Br."), the Examiner's Answer mailed January 5, 2017 ("Ans."), and the Reply Brief filed March 6, 2017 ("Reply Br."). Appeal2017-007355 Application 14/552,086 side wall damage along active device edges. Spec. ,r 1. According to the Specification, by sawing a first cut of Zl on the back-side surface of the wafer substrate, the maximum shift is reduced to which the active devices on the front-side of the wafer would be exposed and the smaller kerf of the second cut of Z2, after laser grooving between the active devices on the wafer front-side to remove metallization, lessens the probability of damaging active areas of the die with its reduced shift. Id. ,r,r 29, 45. Claim 1 is illustrative: 1. A method for sawing a wafer substrate, the wafer substrate having a front-side surface containing active devices separated by saw lanes and a back-side surface having undergone back grinding, the saw lanes having process control monitor (PCM) devices present therein, the method comprising: mounting the wafer substrate onto a carrier tape on the front-side surface; with a blade of a first kerf, W z1, sawing the back-side surface in tracks corresponding to the saw lanes, to a first depth; applying carrier tape to the back-side surface of the wafer substrate; removing the carrier tape from the front-side surface; laser grooving (LG) the saw lanes, to an LG depth, on the front-side surface of the wafer substrate until PCM devices are substantially removed, the LG having a preset beam diameter, WLa; and with a blade of a second kerf, W z2, the second kerf less than the first kerf, sawing the front-side surface of the wafer substrate about the center of the saw lanes to enable the separation of the active devices from one another; wherein WLa>Wz1>WZ2. App. Br. 14 (Claims Appendix). 2 Appeal2017-007355 Application 14/552,086 Appellant's Figures 2A through 2C below illustrate Appellant's wafer dicing process. Spec. ,r 13. ----------·' .+, I 1! \ ... ! l........... . ..... ' : \ · ...... •· ......... ' \\ 30 \ 250 Fl(r 2.A HC. 2B FlG. 2.C Figure 2A above shows blade 5 having width Z 1, Figure 2B above shows laser beam 10 having diameter 25 (width LG) which is close to that of saw lane 20, and Figure 2C above shows blade 15 having width Z2. Spec. ,r,r 5, 30. The Examiner maintains, 2 and Appellant3 appeals, the rejection of claims 1-6 under 35 U.S.C. § 103 as unpatentable over Qiu4 in view of Park. 5 Ans. 2; App. Br. 3. Appellant argues the subject matter of claims 2 The rejection of claims 5, 6, and 10 under 35 U.S.C. § 112(b) as indefinite has been withdrawn. Ans. 2. 3 Appellant is the Applicant, NXP B.V., identified in the Brief as the real party in interest. App. Br. 3. 4 Qiu et al., US 2014/0024199 Al, pub. Jan. 23, 2014 ("Qiu"). 5 Park, US 2006/0169680 Al, pub. Aug. 3, 2006. 3 Appeal2017-007355 Application 14/552,086 1---6 as a group. App. Br. 4. In accordance with 37 C.F.R. § 4I.37(c)(l)(iv), claims 2-6 will stand or fall together with claim 1. OPINION The dispositive issues for this appeal are (1) whether the Examiner erred in modifying Qiu's teaching that active devices are separated from each other with one saw cut at the back-side of a wafer and a laser scribe on the front-side of the wafer with Park's teaching to separate active devices from each other with a saw cut on the front-side of a wafer, (2) whether the Examiner erred in finding that Qiu teaches that the grooving on the back- side of a wafer should be larger than the final cutting width, and (3) whether the Examiner erred in finding that Park teaches a laser grooved trench having a width greater than the width of a mechanical cutter. After review of the arguments and evidence presented by both Appellant and the Examiner, we affirm the stated rejection. It is the Examiner's position that Qiu in view of Park suggests the subject matter of claims 1---6 for the reasons stated on pages 3-7 of the Final Office Action. In the Appeal Brief, Appellant argues that the Examiner's rejection is in error because no reasoning was articulated for sawing both the back-side surface and the front-side surface of a wafer with blades to separate active devices. App. Br. 7. Appellant contends that neither Qiu nor Park suggest separating active devices with saw cuts on both sides because Qiu teaches separation with two saw cuts at the front-side of a wafer and Park teaches separation with a saw cut only on the front-side of a wafer. Id. at 8. Regarding the Examiner's reasoning that the combination of prior art teaches the relationship of WLa>Wz1>WZ2, Appellant contends that the 4 Appeal2017-007355 Application 14/552,086 reasoning does not articulate why a skilled artisan would saw both the back- side surface and the front-side surface of a wafer with blades to separate active devices. Id. at 8-10. In addition, Appellant contends that Qiu teaches away from WLa>Wz1 because Qiu's laser beam produces regions below the front surface over a width less than and included within the width of the grooves. Id. at 11 (citing Qiu ,r 27). Appellant also contends that Park is silent as to the relative widths of the laser beam and the mechanical cutter, therefore, Qiu in view of Park does not teach or suggest the relative kerfs of the saw blades. Id. at 12 (citing Park Figs. 9-12). Appellant argues that unexpected results were achieved from the double-sided sawing, and cites paragraphs 39-46 and Figures 5A and 8 as evidence of such unexpected results, pointing out that paragraph 45 states that the probability of sawing damaging active areas of the integrated circuit device die was lessened. Id. at 10-11. The Examiner responds that a skilled artisan would have substituted Qiu's single step process of laser cutting the front-side surface of the wafer with Park's two-step cutting process of laser cutting and sawing with a blade to improve the devices by allowing the incorporating of testing elements onto the wafer without wasting valuable chip space. Ans. 3--4 ( citing Park Fig. 9, testing elements 910, and Fig. 10, laser cutting 1000). The Examiner finds that Park's laser cutting process requires a larger cutting width for the purpose of completely removing the testing elements followed by cutting with a blade having a smaller width similar to the final laser cutting step of Qiu. Id. at 5. The Examiner additionally finds that Park's disclosure that multiple passes with the laser beam may be used to form the laser grooved trench also suggests forming the trench with a single pass, particularly in the 5 Appeal2017-007355 Application 14/552,086 interest of shortening manufacturing time; thus, a less fine cut would be beneficial. Id. at 6-7 (citing Park ,r 52). Regarding Qiu's cutting widths, the Examiner finds that Qiu uses a laser beam cutter 702 with a width smaller than the width of the cutting operation on the backside of the wafer such that wasted cutting space is on the back side, therefore, Qiu teaches the final cutting operation should have a width less than the width of the cutting operation on the back-side surface (the second kerfWZ2 by Park's blade). Id. at 5, 7 (citing Qiu ,r,r 17, 27). Regarding Appellant's showing of unexpected results, the Examiner finds that it would have been expected to be easier to cut through a thinner rather than a thicker region because there is less material to cut through. Id. at 4. The Examiner also finds that a lower probability of damage to the opposite side of the cutter in a cutting process would have been expected. Id. In the Reply Brief, Appellant argues that there is no reason to substitute Park's two-step process in the process of Qiu because Qiu does not teach or suggest the need to remove test pattern circuitry. Reply Br. 4 ( citing Qiu ,r 3 regarding the desirability to allow for more area on the wafer to be used for forming circuitry). According to Appellant, a skilled artisan would be motivated to use the two-step process of Park itself rather than that of Qiu if it was necessary to remove a test pattern in the saw streets. Id. at 5. Because Qiu teaches using a laser beam to scribe the front-side of the wafer, Appellant asserts that Qiu does not teach or suggest a relationship between the kerfs of two saw blades of W z1> W z2, but only the relative widths of a saw blade and a laser scribe. Id. at 6, 8. Regarding the relative widths of the mechanical cutter and the laser beam of Park, Appellant asserts that the 6 Appeal2017-007355 Application 14/552,086 diameter of the laser beam appears smaller than the width of the saw blade in Park's Figures 10 and 11, e.g., WZ2>WLa, and that the Examiner's position otherwise is not supported by the record. Id. at 7. We review the appealed rejection for error based upon the issues identified by Appellant and in light of the arguments and evidence produced thereon. Cf Ex parte Frye, 94 USPQ2d 1072, 107 5 (BP AI 2010) (precedential) (cited with approval in In re Jung, 637 F.3d 1356, 1365 (Fed. Cir. 2011) ("it has long been the Board's practice to require an applicant to identify the alleged error in the examiner's rejections"). We find Appellant's arguments unpersuasive of reversible error by the Examiner for the following reasons. Appellant does not dispute the Examiner's findings regarding the relative widths taught by Qiu between the final cut and the back-side cut. Instead, Appellant points out that Qiu's final cut is a scribe and not a blade. Appellant's argument is not persuasive because it argues the references individually rather than the combination of art on which the rejection is based. See In re Keller, 642 F.2d 413,426 (CCPA 1981); In re Merck & Co., Inc., 800 F.2d 1091, 1097 (Fed. Cir. 1986). It is also not persuasive because in a determination of obviousness, a reference may be relied upon for all that it would have reasonably suggested to one having ordinary skill in the art. Merck & Co. v. Biocraft Labs., 874 F.2d 804, 807 (Fed. Cir. 1989). The Examiner's finding that Qiu teaches the final cut ("singulation") has a substantially reduced width is supported by the record. Qiu ,r,r 17, 27. Qiu quantifies the width (SI) of the groove (604) on the back-side as approximately 40 µm and the width (S2) of the scribing on the front-side as less than 10 µm. Id. ,r,r 26, 27. 7 Appeal2017-007355 Application 14/552,086 Appellant's argument (Reply Br. 4--5) that a skilled artisan would not be motivated to substitute Park's two-step process on the front-side of the wafer for Qiu's single cutting operation because Park's method can be used alone for removing test circuitry and Qiu does not teach the need to remove test pattern circuitry is not persuasive because the removal of test circuitry is an articulated reason provided by the Examiner for modifying the method of Qiu. The Examiner's reasoning is supported by the record, namely Park. Simply because Park teaches the removal of test circuitry with its two-step process and could be used for this purpose absent combination with Qiu is insufficient to rebut the articulated benefit of the step in Qiu's process. Regarding the relative widths of Park's laser 1000 and blade 1100, the Examiner's rejection relies upon the teachings of Qiu for the relative sizes of both ( 1) the kerf of the saw blade on the back-side of the wafer having a larger width than cutting on the front-side, based on Qiu's teaching regarding wasted space being located on the back-side, as well as (2) the final cut having the smallest width. The Examiner relies on Park for teaching the width of the laser grooving being such that test circuity may be removed. Ans. 3 ( citing Park, Figs. 9, 10). Appellant does not dispute that Park uses laser grooving for the purpose of removing testing elements and the Examiner's findings are supported by the record. Park, Fig. 9 ( testing elements 910) and Fig. 10 (laser cutting 1000 removes testing elements 910). The Examiner further determines that it would have been within the level of skill of one of ordinary skill in the art at the time of the invention to choose the desired width of the laser beam for a particular laser grooving operation to form the laser groove with a single pass, thus drastically shortening the manufacturing time. Ans. 6-7. In the Reply Brief, Appellant 8 Appeal2017-007355 Application 14/552,086 does not dispute that it would have been within the level of skill of one having ordinary skill in the art to select a desired width of the laser beam for a particular grooving operation that removes testing circuity in a single pass, nor does Appellant argue that a grooving operation for the purpose of removing testing circuitry would not have a larger width than both the singulation width and the back-side groove width disclosed in Qui. Therefore, Appellant's arguments regarding the relative widths required by claim 1 are not persuasive because they argue the references individually rather than the combination of the teachings from each reference as applied in the rejection. Regarding Appellant's evidence of unexpected results, a party asserting unexpected results as evidence of nonobviousness has the burden of proving that the results are unexpected. In re Geisler, 116 F.3d 1465, 1469--70 (Fed. Cir. 1997). "[I]t is not enough to show that results are obtained which differ from those obtained in the prior art: that difference must be shown to be an unexpected difference." In re Klosak, 455 F.2d 1077, 1080 (CCPA 1972). Moreover, "when an inventor tries to distinguish his claims from the prior art by introducing evidence of unexpected 'synergistic' properties, the evidence should at least demonstrate 'an effect greater than the sum of the several effects taken separately."' Merck & Co., 874 F.2d at 808 (citing Sakraida v. Ag Pro, Inc., 425 U.S. 273,282 (1976)). Appellant's evidence shows no more than "the smaller kerf of the second cut of Z2, after the laser grooving, with its reduced shift, lessens the probability of the sawing/singulation process damaging active areas of the integrated circuit device die" (Spec. ,r 45). Such evidence is insufficient to rebut the 9 Appeal2017-007355 Application 14/552,086 Examiner's obviousness determination, particularly in view of Qiu's teaching that the last singulation cut has the smallest width. For the foregoing reasons, we affirm the Examiner's rejection of claims 1-6 under 35 U.S.C. § 103. CONCLUSION The Examiner's rejection of claims 1-6 under 35 U.S.C. § 103 is affirmed. No time period for taking any subsequent action in connection with this appeal maybe extended under 37 C.F.R. § 1.136(a)(l)(v). AFFIRMED 10 Copy with citationCopy as parenthetical citation